- 1 Introduction
- 2 What causes keratinocyte cancers?
- 3 How can keratinocyte cancers be prevented?
- 4 How are keratinocyte cancers diagnosed?
- 5 How are keratinocyte cancers treated?
- 6 What happens after treatment?
- 7 What happens if the cancer comes back or spreads?
Keratinocyte cancer, previously called non-melanoma skin cancer, includes two types of skin cancers: basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).
These types of skin cancers are very common in Australia. They make up the majority of the estimated one million skin cancers diagnosed and treated each year, and cost our health system hundreds of millions of dollars every year.
Very few people in Australia die from BCCs or SCCs. Most of these cancers are discovered and treated before they can spread. Some grow very slowly or stay the same for years. Others can spread into the layers under the skin, or nearby parts of the body. Rarely, a BCC or SCC will spread throughout the body and invade other organs.
This guideline is for health professionals, including general practitioners (GPs), surgeons, pathologists, dermatologists and oncologists. It contains recommendations about how to prevent, diagnose and treat BCC and SCC.
What causes keratinocyte cancers?
The most common cause of BCCs and SCCs is being out in the sun without strong protection against ultraviolet (UV) rays. These cancers are most common in people who have been sunburned during childhood, outdoor workers, people with naturally pale skin, people in the northern parts of Australia and people who use tanning beds. Both BCCs and SCCs are common on parts of the body that are exposed to sunlight, such as the head and neck, arms and legs.
Other causes include genetic skin conditions, and having a weak immune system due to a medical condition (e.g. HIV-AIDS, or chronic lymphocytic leukaemia), or due to drug treatment that weakens the immune system (e.g. for organ transplants). People with these conditions have a very high risk of skin cancer.
How can keratinocyte cancers be prevented?
Advice for preventing BCCs and SCCs is the same as for preventing melanomas: cover up with clothing, sunscreen, a broad-brimmed hat, shade and sunglasses whenever the UV index is 3 or higher. People can still get enough vitamin D while protecting themselves against skin cancers.
Drug treatment to prevent skin cancer is sometimes prescribed for people who have a very high risk of skin cancer (e.g. people with rare skin conditions or people who have already had several skin cancers).
Skin cancers can be prevented by finding and treating them at a precancerous stage. GPs should estimate each patient’s risk. Skin checks are not routinely recommended for people with no unusual skin spots or a low risk of skin cancers, but people at high risk should have regular skin checks. GPs should consider performing skin checks during physical examinations for anyone aged over 40 years with one or more risk factors (or younger people with sun-damaged skin). People with very high risk need to have skin checks more often. For people at high risk, it may be best to have skin checks done by a dermatologist or other doctor with special training and experience in skin cancer.
Organ transplant clinics should give patients information and check-ups for skin cancer.
People should also look out for new skin spots. A spot should be checked by a doctor if it has grown or changed shape or colour over weeks or months, looks different or stands out from other spots, is painful, bleeds easily, or seems to be a sore that doesn’t heal. When someone notices a new skin spot, their doctor should always check it carefully.
How are keratinocyte cancers diagnosed?
Most BCCs and SCCs can be recognised by doctors by their appearance, along with information about whether the spot has changed over time and any symptoms (e.g. itch or pain).
BCCs can be flat, knobbly or look like a scar, and may be skin-coloured or have different colours. They don’t usually cause any symptoms, but are sometimes itchy. Their surface may become raw (ulcerated). Many stay small, but some types can grow as wide as 10cm if not removed.
SCCs usually have crusty layer over top of the cancer. Bowen’s diseasecSCC in situ (also known as intra-epidermal SCC) and actinic keratosis (previously called solar keratosis) are early, pre-cancerous growths that can develop into SCC. Many spots that could have become SCCs are discovered and treated at a precancerous stage. Anyone who has had an actinic keratosis should have regular skin checks, to identify SCCs as early as possible.
Doctors can use a hand-held magnifying device (dermatoscope) to examine skin spots more closely. Sometimes it is hard to recognise a skin spot from its appearance. If there is any doubt, the doctor should remove the whole growth, or take a sample (biopsy), to be examined by a pathologist.
When a BCC or SCC is diagnosed, the doctor assesses how likely it is to spread and cause health problems. Some rare types of BCC and SCCs are known to have a high risk for spreading and invading other organs, or recurring after being removed. Other types tend to grow slowly or stay the same over time.
How are keratinocyte cancers treated?
Cutting out the whole cancer in one operation (surgical excision) is the most common treatment for BCCs and SCCs. Other treatments include freezing (cryotherapy), killing the cancer with an electric current and then scraping out the dead tissue (electrodessication and curettage), chemical treatment (e.g. creams) and radiation treatment (radiotherapy).
Surgery generally gives the best chance of a cure. It is recommended for skin cancers that have a higher risk of growing back. Sometimes radiotherapy is used as well as surgery to improve the chance of cure. For skin cancers with a low risk of growing back, the person can be offered other treatment choices.
GPs can remove most BCCs and SCCs. GPs should refer patients to a specialistMedical practitioners who through training, experience and peer opinion specialise in the management of keratinocyte cancers if the cancer is in a difficult area (e.g. face, ears, fingers or lower leg).
Surgery for skin cancers involves cutting around the cancer to remove it, and removing a margin of healthy skin around the edges and under the cancer below the skin.
The main aim of surgery is to avoid leaving behind any cancer that could grow back. The next most important aim of surgery is to save as much healthy tissue as possible, so that the part of the body from which the cancer was removed still functions well and looks as normal as possible.
Surgery for skin cancers is usually done under local anaesthetic and the patient can go home afterwards. Surgery could leave a scar, depending on the type of cancer and where it is on the body.
After surgery, the pathologist examines the whole removed piece of skin. The pathologist checks whether a wide enough margin around the cancer has been cut out. How wide is safe depends on the type of cancer and how it looks under the microscope.
If the pathology report says the cancer was low risk and the margin was wide enough, no more treatment is needed. If the pathologist finds that the cancer was high risk or the margin was too narrow, the person may need more surgery, with or without radiotherapy.
Mohs surgery is like surgical excision, but the removed cancer and surrounding skin is checked under a microscope straight away, before stitching up the wound. If the microscope shows that some of the cancer was too close to the edge of the piece removed, the surgeon slices more away.
Mohs surgery is usually performed under local anaesthetic. Usually the open surgical wound is covered and person can sit in a waiting room between each stage of the operation.
The main advantage is that it allows the least possible amount of skin to be removed, while finding out straight away if any cancer was left – instead of waiting several days after the operation for the pathology report. The main disadvantages are that it takes time, specially trained staff and special equipment, and is only available at some specialised clinics in Australia.
Mohs surgery can be considered for BCCs that don’t have easy-to-see edges, BCCs on the face, BCCs that have come back after previous treatment, or large BCCs, and some other types of skin cancer.
Some small BCCs and pre-cancerous growths can easily be frozen off in the doctor’s office using liquid nitrogen (cryotherapy). Cryotherapy leaves a white patch on the skin, so is usually not used on the face or for people with dark skin. Long-term follow-up is needed after cryosurgery for BCCs, because there is a small chance they could grow back years later.
Electrodessication and curettage
Some small BCCs and pre-cancerous growths can be removed using an electrical current that kills the cancer (electrodessication and curettage). This treatment is quick and can be done in the doctor’s office.
Radiotherapy can sometimes be as effective as surgery for curing cancers that are diagnosed early enough and don’t have a high risk of growing back. It might be the best choice treatment for some cancers where surgery would remove too much tissue (e.g. for cancers on eyelids, lips or nose) or could damage nerves, or for people who cannot have surgery.
Radiotherapy can also be added to surgery to improve the chance of a cure (e.g. when the pathology report says the cancer was high-risk or the margin of healthy skin cut out was too narrow). When radiotherapy is given after surgery, it should be within 6 weeks of the operation. It is also used to treat skin cancers that have spread to other body parts.
Radiotherapy involves repeated doses over several weeks (e.g. 4–12 visits over 1–2 weeks for a small cancer, or 15–30 visits over 3–6 weeks for a large cancer). Possible side effects include redness and peeling of the skin, rawness and hair loss. Some skin changes can occur months or years after treatment.
Recent advances in radiotherapy equipment and techniques allows radiation to be directed more precisely to the shape of the cancers, and allow more precise dose.
Chemical treatment (creams and gels)
Another way to remove skin cancers and pre-cancerous growths is by applying creams or gels to the surface. Imiquimod cream can be used to remove some types of BCCs when surgery is not an option. Before starting treatment, a biopsy should be taken to be sure that the growth is a BCC. Imiquimod cream is usually applied at home by the patient three - five times per week and left on all day. Possible side-effects include redness, scabbing, or open sores.
Actinic keratosis (a type of pre-cancerous growth) can be treated with imiquimod cream, 5-fluorouracil cream, diclofenac gel or ingenol mebutate gel. Bowen’s diseasecSCC in situ (also known as intra-epidermal SCC) (an early, pre-cancerous form of SCC) can be treated with 5-fluorouracil cream.
Actinic keratosis, Bowen’s diseasecSCC in situ (also known as intra-epidermal SCC), and some types of BCCs can be treated with light treatment (photodynamic therapy). Photodynamic therapy involves applying a cream to the cancer to make it sensitive to light, then using a special lamp. This treatment is useful for people who have precancerous spots over a large area of skin. It is not recommended for SCC. Special training and equipment is needed to do photodynamic therapy, so it is only available in some clinics.
Oral medicines are also available for treating BCC. They are sometimes used in combination with radiotherapy and surgery. These medicines are mainly used for people who keep getting BCCs due to genetic conditions.
What happens after treatment?
When someone has a BCC or SCC removed, their doctor should carefully explain the risk of new cancers, or treated cancers growing back. Almost half of people who have had a BCC removed will have a new BCC within 3 years. Almost one in five people who have had a SCC removed will have a new SCC within 3 years.
When skin cancers have been treated by a specialistMedical practitioners who through training, experience and peer opinion specialise in the management of keratinocyte cancers, the specialist will usually provide check-ups for the first few years. How often the person needs a check-up will depend on the type of cancer and the pathology report. Check-ups should include full skin checks and checking to make sure the cancer has not spread from the skin.
After the first few check-ups by a specialistMedical practitioners who through training, experience and peer opinion specialise in the management of keratinocyte cancers, the person will usually go back to their GP for long-term care, which will include skin checks. Anyone who has had a skin cancer should have a yearly skin check for the rest of their life.
What happens if the cancer comes back or spreads?
Less than one in 50 people will have their BCC grow back after it has been completely removed surgically. BCCs very rarely spread to other body parts. It is uncommon for SCCs to come back or spread to other body parts. When a BCC or SCC comes back, it usually happens within 2–3 years.
If there are signs that a skin cancer has spread to the nearby lymph nodes (e.g. if they are swollen and tender), a sample is taken with a needle for testing under the microscope.
If a skin cancer may have spread by growing along the nerves in the skin, the person should be referred to a specialistMedical practitioners who through training, experience and peer opinion specialise in the management of keratinocyte cancers. If the cancer has spread from the skin into other parts of the body, the person should be referred to a specialistMedical practitioners who through training, experience and peer opinion specialise in the management of keratinocyte cancers. Sometimes the best treatment involves a team of doctors with different types of expertise (e.g. head and neck surgeon, reconstructive surgeon, dental oncologist, surgical oncologist, radiation oncologist and medical oncologist).
Surgery, radiotherapy, chemotherapy, or a combination of treatments may be needed. Drug treatment (e.g. cemiplimab) should be considered for people with SCC that has spread from the skin, but who cannot have surgery or radiotherapy.